Embolism, or embolus as it is known in medicine, is a particle that moves through our blood vessels, whether in veins or arteries. The embolus can be formed by a variety of elements, such as: gas bubbles, bacterial clumps, small firearm projectiles, needles, among others.

What is Embolism?

But, in most cases, embolism is composed of clotted blood cells. A blood clot is called a thrombus, and a moving blood clot is called a thromboembolus. As the embolism moves through the body’s blood vessels, it is likely to reach a passage it cannot get through. It remains there, blocking the blood behind it.
The cells that normally receive their blood supply through this passage are starved of oxygen (ischemia) and die. This condition is called embolism.

Types of Embolism

There are several types of embolism:
Pulmonary Embolism: an embolus, usually formed in the leg (sometimes known as deep vein thrombosis or DVT), gets lodged in one of the arteries of the lungs. Many emboli are dissolved by the body and go away on their own; however, severe pulmonary embolism can cause death1.
Cerebral Embolism: if a blood clot travels to the brain, this causes a stroke (CVA) or a transient ischemic attack (TIA), also known as a mini-stroke2.
Retinal Embolism: small clots that do not block a large artery can block the tiny blood vessels that supply the retina at the back of the eye. The result is usually sudden blindness in one eye.
Septic Embolism: occurs when particles created by infection in the body reach the bloodstream and block the blood vessels.
Amniotic Embolism: not all emboli are made of clotted blood. During pregnancy, the uterus is filled with amniotic fluid, which protects the fetus. Amniotic fluid can embolize and reach the mother’s lungs, causing pulmonary amniotic embolism.
Air Embolism: divers who surface rapidly can develop an air embolism. These air bubbles can block the arterial blood flow.
Fat Embolism: if fat or bone marrow particles are introduced into the bloodstream, they can block blood vessels just like a blood clot or an air bubble3.

Causes of Embolism

Most embolisms occur in people who have a predisposition or risk factors for blood clot formation. These factors can be smoking or heart disease.
In addition to these, there are other causes for the different types of embolism and they include high blood pressure, atherosclerosis (buildup of fatty plaque in the blood vessels), and high cholesterol.
The main cause of most pulmonary embolisms is deep vein thrombosis (DVT). This is a condition in which leg veins develop clots.
Natural agents in the blood usually dissolve small clots without causing blockages. Some clots are too large to dissolve and are big enough to block large blood vessels in the lungs or brain.
Conditions where blood flow is slow in the legs can promote clotting. Some people can develop thrombosis or pulmonary embolism after sitting on long flights or after the leg is immobilized in a cast, or after prolonged bed rest without moving the legs.
Other causes associated with DVT or pulmonary embolism include cancer, previous surgery, broken leg or hip, and certain genetic conditions that affect blood cells, where the chance of clot formation is much higher.

Symptoms of Embolism

The symptoms of embolism depend on where it developed and all of them are due to the sudden interruption of blood supply. Some of these symptoms include:

  • Shortness of breath, rapid breathing or wheezing
  • Bloody sputum
  • Cough
  • Vertigo, dizziness
  • Loss of consciousness
  • Chest pain
  • Increased heart rate
  • Back pain and lower back pain
  • Tired or heavy legs, or warm skin on the legs, visible veins, swollen legs, and pain or fatigue in the feet.

Complications of an Embolism

The complications of an embolism vary according to the type of embolus and may be:The blockage suffered in the vessel might not be total, and in this case, simple local circulatory insufficiencies develop. Once the embolus is dissolved by the vessel, a secondary thrombus may develop on it, which often conceals the first.
If the vessel obstruction is total and the blood flow insufficient, infarctions occur. If the emboli contain pus, metastatic abscesses appear.
If emboli consist of live pathogenic bacteria, foci of septicemia develop. If emboli are cancer cells, metastases of tumors arise.

Diagnosis of Embolism

There are several ways to diagnose embolism. First, the symptoms described by the person who presents the condition are checked, and, when appropriate, risk factors and the probability of thrombosis are also analyzed.
For Pulmonary Embolism, sometimes an X-ray exam (called a phlebography) is needed. Contrast is injected into a vein in the foot and the reflux can be followed by X-ray images. The aim is to create an image of the blood flow in the lung.
In addition to this chest radiograph, a ventilation/perfusion scan (V/Q scan) can be performed to see if anything is blocking the blood flow through the lungs. Other tests include computed tomography or pulmonary angiography.
If there is reason to suspect thrombosis, the first step is usually to order an ultrasound of the vascular network (Doppler). This test provides an image of the blood flow. Today, there are modern devices and experienced operators capable of producing a definitive report.
For deep vein thrombosis, Doppler studies of the legs, venograms, or impedance plethysmography (IPG) of the veins can be performed to detect a blood clot.
It is common to have increased blood clot formation, which can be measured by the D-dimer value (Screening test for deep vein thrombosis; assessment of acute myocardial infarction, unstable angina, disseminated intravascular coagulation).
In patients with thrombosis/embolism, D-dimer values are usually significantly elevated. However, a high D-dimer value is not definitive proof of thrombosis.

Treatment and Prevention

Treatment for thromboembolism (blood clot embolism) involves anticoagulant or thrombolytic medications. Anticoagulants, such as heparin or warfarin, are the main medications given for pulmonary embolism4.
Anticoagulants prevent further blood clotting. Thrombolytics, such as alteplase and streptokinase, help the body dissolve the original clot.
The most effective way to prevent pulmonary embolism is to avoid letting deep vein thrombosis form or start to move in the blood vessels. If you have DVT, you may be prescribed an anticoagulant.
Anticoagulants can also be given to people with embolism to prevent the condition. They can also help protect against strokes.
Non-drug methods to help prevent thrombosis and embolism include the use of compression devices and compression stockings (to ensure blood does not pool in the legs), and frequently stretching, massaging, and moving the leg muscles if you have been inactive for a long time.
You can also reduce your risk factors for developing blood clots, such as:

  • Avoid cigarette use
  • Maintain a balanced diet
  • Keep weight appropriate for your height
  • Exercise daily
  • Control blood pressure

See Also: Thrombophilia – During Pregnancy or Otherwise, It Must Be Treated Photos: Bruceblaus